The invention relates to an automatic fruit bag sheathing device, which comprises a motor, a support seat, a rocking bar mechanism, fruit bag support plates, fruit bag fixing screw bolts and chucks, wherein the rocking bar mechanism comprises a compression round post, a long rubber rod and opening sealing jaws, the compression round post is in symmetrical arrangement, the motor is fixedly arranged on the support seat through a motor seat, an output shaft of the motor is connected with a rocking bar shaft through a shaft coupler, two sides of the support seat are symmetrically provided with the fruit bag support plates, the fruit bag fixing screw bolts and the chucks are symmetrically arranged on the two fruit bag support plates, short rubber bars corresponding to the compression round post are symmetrically arranged on the two chucks, the opening sealing lower jaw is transversely spanned between the two chucks, the opening sealing upper jaw and the opening sealing lower jaw are in symmetrical structure, notches are respectively arranged in the middle parts of the upper jaw and the lower jaw, two sides of the notches are respectively provided with grooves, and electric heating plates are arranged in the grooves. The automatic fruit bag sheathing device adopts the single motor for driving rocking bars to rotate, the bag taking, bag supporting and bag sealing operation of fruit bags can be automatically realized, the structure is simple, the speed is high, the reliability is realized, the operation of the whole bag sheathing process is easy, the speed and the efficiency are high, and the automatic fruit bag sheathing device can be widely applied to the fruit bag sheathing field operation production.